One-third of Republicans Trump supporters said they would not support the party in the general election if the businessman is blocked from the nomination. They said they would instead vote Democrat, vote third-party or sit out the election.

Sixty-six percent said they would support the GOP's nominee anyway.

A contested convention could hurt the GOP in November no matter what, the poll found. Fifty-eight percent of Trump supporters said they would stay with the party, while 16 percent would leave and 26 percent said they didn't know.

The poll surveyed 468 Republican Trump supporters and has a margin of error of 5.3 percentage points.